Flotation units and systems employing the same



April 29, 1969 w. s. ETTINGER FLOTATION UNITS AND SYSTEMS EMPLOYING THESAME Filed April -15, 1968 FlGl i/f e l i ENTOR WIL AM S. TTINGER M24/@mi HIS ATTORNEY V.. WB

United States Patent O U.S. Cl. 114-68 8 Claims ABSTRACT OF THEDISCLOSURE For contributing to the keeping of a boat or other craftailoat in an emergency, a fully organized, selfcontained otation unit isprovided which includes as one of its components a rigid carryingmember, adapted for `quick and easy attachment to the ceiling of acompartment or room of the craft, and upon which all the othercomponents of the unit, in fully operative association with one another,are compactly mounted.

The other components of each unit desirably comprise a tank or cylindercontaining an appropriate inflating gas, such as carbon dioxide, anelastic bladder, and connecting means providing communication betweenthe tank and the bladder, and including a supply valve, a pressurelimiting regulating valve, and a pressure relief valve. The bladder issurrounded by an envelope of strong, freely exible, inextensible wovenfabric for limiting expansion of the bladder and protecting it againstpuncturing. The bladder and envelope, compactly folded, are containedsnugly within an easy-tear container of small capacity which normallyholds them to the carrier, but which tears apart in response to inatingpressure.

The connecting means between the tank and the bladder also desirablyincludes a distinct supply valve and heat responsive means for openingsuch valve in case of re.

Provision is made for controlling a group of the units from a commonremote control station, either by turning on the units singly or byturning on a plurality of the units simultaneously.

Various proposals have been made for equipping boats or other craft withone or more flotation bladders for keeping the craft afloat in anemergency. Frequently the structure of the craft has been modified toaccommodate the bladders and associated mechanisms, and as a rule theseveral associated mechanisms have been brought into association withone another for the first time by mounting them separately on the craftand then connecting them with one another. In other instances amultiplicity of bladders have been connected to a common source ofinilating gas under pressure through an elaborate system of pipes, whichincluded a single common pipe adjacent the source, the arrangement beingsuch that part or all of the bladders could be put out of commissionbefore or after inflation by damage to the pipes or part of them.

It is a primary object of the present invention to provide a fullyorganized, self-suicient, flotation unit which includes as one of itscomponents a rigid carrier member adapted for quick and convenientattachment to the ceiling of a compartment or room of the craft, andupon which all of the other components of the unit, in fully operativeassociation with one another, have been compactly mounted. With such anarrangement each unit has its own individual gas supply, the supplylines are localized and kept short, and other advantages are realized.

It is a further object of the invention to soarrange the components of aunit that the unit will be neatly ICC organized, convenient to store,handle and ship, easy to install, and inconspicuous when installed.

In referring to the units as inconspicuous, it is not meant that a unitis so small as to escape notice, but rather that it is relativelycompact in its normal dimensions as compared with its inated dimensions,that it is not unsightly, and that it can be installed in out of the waylocations where it will not materially curtail or interfere with thenormal use of the room or compartment in which it is installed.

To these ends, the unit desirably includes in addition to the rigidcarrying member already referred to and a tank or cylinder of gas underhigh pressure mounted thereon, a bladder of resilient, stretchable,foldable material, also carried by the support, and connected to thetank for inflation by it when required.

The bladder desirably has considerable strength, but it can be readilypunctured by a sharp object, and it can be strained in use to thebursting point unless ination is limited and the bladder issubstantially reinforced. It is accordingly a feature that the bladder,with the exception of a thickened neck portion, is enclosed in anenvelope of strong, tough, flexible, readily foldable, nonstretchablewoven fabric when limits expansion and deformation of the bladder, andprotects it against puncture.

The bladder and envelope, if permitted to dangle from the carrier, wouldbe awkward to store, ship and install, and would be unsightly and in theway when installed. The unit is therefore made to include a container inwhich the bladder and envelope are compactly folded and snugly enclosed.The container has a portion which is firmly and permanently axed to therigid carrier, but the remainder of the container is provided with oneor more easy-tear lines, so the container will be incapable ofsubstantially opposing ination, and will be torn apart as the bladderexpands under inating pressure.

The connection from the tank to the bladder includes a normally closedsupply valve and a constant pressure regulator to preventover-inflation. Since the sudden loss of pressure of the gas as itenters the bladder will cause some of it to be converted to solid form(as carbon dioxide to Dry Ice), which will not at once affect thepressure regulator, but may later result in a pressure higher than issafe or desirable, a relief valve is provided in direct communicationwith the bladder, set for a safe pressure, but one which is higher thanthat of the regulator.

The supply valve may be opened by direct manual operation, or it may bemanually opened by remote control. Where two or more units are employedin a system, they can be opened individually or by group action throughremote control.

It is important feature that a gas supply valve may be provided |whichis automatically opened in response to heat generated by fire. In thissituation, if the bladder and envelope are destroyed by the fire, thegas Iwill be poured out rapidly onto the fire.

Other objects and advantages will hereinafter appear.

In the drawing lwhich forms part of this specification,

FIGUR-E l is a view in elevation in which a single illustrativeflotation unit is shown in installed condition, together with anelectrical system for either remote manual control, Vdirect manualcontrol, or automatic water level control, of the unit supply valve;

FIGURE 2 is a somewhat idealized showing of a portion of the unit ofFIGURE l in an inflated condition;

FIGURE 3 is a plan view showing the bladder, the envelope, and a portionof the rigid support, prior to folding of the bladder and envelope, andthe enclosure of them in the container;

FIGURE 4 is an electrical diagram showing both manual and automaticmeans for bringing about inflation as required where a number of unitsare included in a system; and

FIGUiRE 5 is a transverse sectional view through a seat of a small openboat and showing how an ination unit may be removably attached thereto.

In FIGURE l the interior of a compartment is shown in which a flotationunit 10, illustrative of the invention and embodying features thereof,is secured by suitable fasteners, such as screws -12, to the compartmentceiling 14. The fasteners 12 are passed upward through a carrier member16, which may advantageously consist of a flat, rigid sheet of plywoodor composition board, and which constitutes a significant part of theunit. The carrier member 16 serves as a common support for all the othercomponents of the unit.

The unit includes a metallic supply tank or cylinder 18 which normallycontains a suitable gas, preferably carbon dioxide, maintained in liquidform under a pressure suitable for that purpose. The tank 18 is held inplace on the carrier by metallic straps 20 (one shown), the outturnedends of which are secured to the carrier member 16 by screws 22.

A channel of communication is provided between the tank 18 and thethickened neck 24 of a stretchable, elastic -bladder 26, desirably ofrubber. The communicating channel includes tubing 28 having parallelbranches 30 and 32. In one of the branches, 32, there is provided anormally closed supply valve 34 which may be operated manually orautomatically for permitting inflating gas to flow from the tank 18 intothe bladder 26. After passing the branched portion of the tubing, thegas flows through a settable regulating valve 35 designed to limit thepressure of the gas in the infiated bladder substantially to apredetermined, operating value, well within the limit of safety.

Since inflation of the bladder is attended by sudden expansion of thegas, and marked loss of temperature, a p0rtion of the gas may bedelivered to the bladder as Dry Ice. As the Dry Ice sublimates later, itmay tend to increase the bladder pressure beyond a safe or desirablelimit. A relief valve 36, set for a safe pressure, but one somewhathigher than the setting of the regulating valve, is accordingly providedin direct communication with the interior of the bladder.

In the other branch 30 of the tubing 28 a valve 38 is provided which isnormally held closed by a low melting solder, but which is connected toa spring 40 that constantly urges the valve in an opening direction. Ifa lire occurs sufiiciently near at hand to melt the solder, the valve 38is automatically opened by the spring 40, and the gas is released fordischarge into the bladder. In such a situation, however, the bladderwould most probably be burned or melted away, and the gas would bedischarged into the atmosphere. Since, as is well known, carbon dioxideis incombustible, will not support combustion, and is heavier than air,it will blanket and combat the fire. The flotation unit has theadditional advantages, therefore, of serving as an automatic fireextinguisher.

The inflatable, stretchable bladder 26 is contained within an envelope42 of freely fiexible, strong, inextensible woven fabric, such as nylon.The envelope 42 has somewhat more superficial area than the uninflatedbladder. It is stronger and tougher than the bladder, and serveseffectively to protect the bladder against puncturing. It also supportsthe bladder from without, reinforcing the bladder, limiting theexpansion of the bladder, and protecting the bladder against burstingunder the strains to which the inflated bladder is subjected in anemergency. The envelope further controls to a substantial degree theshape of the inflated bladder, a feature of advantage which will bediscussed at a subsequent point. The envelope and bladder may bespecially reinforced for controlling the shape of the inflated bladder.

The strength and thickness of the bladder walls, the

strength and weight of the nylon, and the shape of the bladder andenvelope all admit of extensive variations to meet varying needs andlimitations imposed by different craft, and by craft compartments ofvarying size, shape and locations.

A typical uninflated bladder and unconfined envelope are shown inrelation to one another and as if laid out over a portion of the carrierin FIGURE 3. If the bladder and envelope were permitted to dangle fromthe carrier or merely to hang from the bladder neck, the structure wouldbe unsightly, could prove a substantial nuisance, and the bladder neckmight be choked off to an 0bjectionable extent. The unit would beawkward to store, handle and transport before installation, and would belikely to be damaged in transit. It is, therefore, important to make aneat, compact package of the entire unit, but in such a way that nosignificant resistance to inflation of the bladder will be created bythe packaging means.

To this end a container is provided of relatively flimsy material, sayin the form of a paper bag, having a reetangular bottom. The portion ofthe carrier upon which the container is to be placed may be covered withtacky adhesive. The base of the container, which may have holes ofsubstantial size in it, may also be covered interiorly with tackyadhesive. The envelope 42 and the contained bladder 26, in the flatrelation yshown in FIG- URE 3 and with the bladder neck free, are foldedin along longitudinally extending lines indicated by the arrows 46-46and 48-48. The envelope 'and bladder are then cross-folded successivelyalong cross lines indicated by the arrows 50-50, 52-52 and 54-54, andplaced in the container, so that the bottom of the container 44 becomesadhered to the mounting member y16 and the envelope 42 becomespermanently attached through the container base, and directly, to themounting member 16.

The mouth of the container is then closed and sealed, to confine thebladder and envelope snugly, the neck of the bladder is connected to thetubing 28 as shown in 'FIGURE 1, and the bladder neck is connected tothe mounting member 16 by neck embracing staples 56.

While the container is, as stated, of relatively flimsy material ascompared with the bladder and the envelope, it is of adequate strengthto prevent separation or disarrangement of the package components duringordinary use. iPrior to installation the container may be tied snugly tothe carrier member 16, though such ties should be removed uponinstallation. lIf the container is made of paper, it will be providedwith a peripheral easy-tear line in the location marked 58, near thearea of union with the mounting member. If of woven fabric, thecontainer will desirably be composed of upper and lower parts unitedlong line 58, by a seam in which weak thread is used for the stitching,capable of being readily broken by inflating pressure.

In FIGURE 1 a system is illustrated in which a single unit is used, theelectrical control system being shown in broken lines. A source ofelectrical energy 60, shown as a battery, has one of its terminalsconnected to ground and the other connected through a conductor 62 to aterminal 64, where the circuit is divided to provide parallel conductivepaths.

One of these paths includes a normally open switch 66, a conductor 68and a solenoid winding 70 to ground. The solenoid armature 72 isconnected to the valve 34 and is biased toward the closed position inwhich it is shown in FIGURlE l, but when the solenoid iselectromagnetically drawn to the left to open the valve, it is desirablydetained in that position by a detent (not shown).

The other circuit path includes a conductor 74, a normally open switchwhich is contained in a water-tight housing 76, and a conductor 78 whichis connected to ground through solenoid winding 70. The housing 76carries an external arm 82 on which a lever 84 is pivoted. The levercarries at one end a float 86, and at the other end a switch actuatingprojection 88 which acts through a water-tight rubber cap 90 of thehousing I'76 to close the switch within the housing when water reaches apredetermined level in the normally dry bottom of the compartment.

While the control system described provides means for automaticallyopening valve 34 in response to the rising water, and for opening thevalve manually from a remote control station, it is also possiblemanually to engage and actuate the solenoid armature for opening thevalve.

In FIGURE 4 a multiple unit system is shown in which, by way ofillustration, three of the flotation units are provided, eachindividually operable from a remote control station, all operable inunison from said station, and each operable automatically through itsindividual water level control switch. In the main, the circuits foreach solenoid winding, on an individual basis, are the same as thosedescribed for the single unit system of FIGURE l, and the same referencenumerals have been applied to corresponding parts, but with the lettersa and b added, respectively, to the circuit elements associated 'withthe second and third units.

At the same remote control station at which switches 66, 66a and 66h arelocated, a common switch 22 is provided for simultaneously opening thesupply valves of all three lunits. The input side of switch 92 isconnected to the conductor 62, and the switch is adapted to be manuallyclosed simultaneously on terminals 94, 94a and 94h, the terminals b'eingconnected, respectively, through conductors 96, 96a and 9611 withconductors 68, 68a and 68b.

The only part of a flotation unit which has a specific gravitysubstantially greater lthan one is the tank 18, and it may be very smallin size. Carbon dioxide in liquid form has a specific grafvity of 1.1and hence two liters would weigh 2,200 grams. Since the molecular weightof the gas is 44, the gas weighs Ia little less than two grams perliter, and two liters of the liquid would provide 1,000 liters of gas atatmospheric pressure, enough to provide 1,000 ykilograms of buoyancy.

The problem of bladder and envelope strain is quite complex, involvingmany factors.

If a bladder is inflated only to, or slightly above, atmosphericpressure, it will be placed under little or no strain prior tosubmersion or partial submersion. This is frequently desirable, whereverpracticable, because a unit inflated substantially above latmosphericpressure will generally be placed under greatest strain either in thecourse of submersion or before it ever comes into contact with thewater. Units are preferably not installed deep in the hold of a ship, insuch locations and under such conditions that they would be likely tointerfere with the inherent stability of the ship, tending to induceoverturning as the ship rolls in a storm, or to establish and maintain alist. In most situations the units are most advantageously installed notsubstantially below the normal line, and preferably 'higher in the craftthan the normal -water line.

The regulator should generally be set to limit inflation to a pressurenot very much above atmospheric pressure, and the relief valve should beset to let off gas only at a pressure somewhat above that for which theregulator is set. The higher setting of the relief valve is necessary inorder to avoid the wasting of gas. The pressure within the bladder willvery as the oraft rolls and pitches, being increased as the yunit isforced under the water, and there `should not be a discharge of gas,followed by replenishment, every time such an increase occurs.

Although increased pressure of the gas is necessarily attended by areduction of volume, submersion of the bladder does put the bladder andenvelope Walls under tensile strains. This is true because a sphere hasless surface area than any other solid figure. (Inflation of anyballoon-like structure bulges the sides, straining them toward sphericalform. IForcing a bulged side to a ilat condition contracts the volume ofthe bladder and thereby compresses the gas.

The strengths of the bladder and the envelope materials can be chosen tomeet particular needs, but in the interest of economyV no heavier gaugematerials should be employed than are practically necessary to make dueallowance for deterioration with age, and to provide a reasonable factorof safety. The units should be checked periodically, according to arigid Schedule, as a matter of course.

The shape of the envelope has a bearing upon the strain to which thebladder and the envelope are subjected. The greater the internalthickness between the upper and lower walls of the inflated bladder, thegreater will be the potential buoyancy in relation to the horizontalcrosssection of the inflated bladder, and the greater will be thepressure per square inch tending to burst the bladder and to rupture theenvelope.

To illustrate, we may assume that in a particular case a potentialbuoyant force of one thousand kilograms is required of a unit. If theenvelope -were made cubical in shape, measuring one meter along eachedge, it would exert a total upward thrust of one million grams whenfully submerged, on a horizontal surface of 10,000 square centimeters,or one hundred grams per square centimeter, about one-tenth of anatmosphere. The internal pressure lapplied equally in all directionswithin the bladder would then exceed the external atmospheric pressureby, roughly, ten percent. This would mean, however, that the volume ofthe gas within the bladder has been reduced by deformation of thebladder to about ninety percent of the initial volume of the inflatedbladder, with an over-all contraction of the bladder. There would beincreased tension, chiey in those portions of the bladder not yetsubmerged, caused by the fact that the bladder would be forced to aflattened-out condition, with loss of volume.

If, however, the thickness or depth were divided by four and thehorizontal cross-section were multiplied by four, the volume would stillbe the same as before, and the potential buoyancy would remainunaltered, but the total buoyancy would be distributed over four timesas much horizontal area and would amount to only twentyfive grams persquare centimeter, increasing the internal pressure by only 2.5 percent.The longitudinal and transverse strains would have this new value persquare centimeter, and would be proportional in total amounts to thetransverse and longitudinal vertical cross-sectional area, respectively.The tensions in the materials produced by these strains would,therefore, be reduced by making the length and width substantiallygreater than the thickness.

The foregoing discussion would be strictly true for a static conditionof the craft on an even keel. As the craft rolls and pitches, thehorizontal projection of the bladder and envelope is diminished, andthis causes an increase of pressure lwithin the bladder. When freeportions of the bladder stand higher than the carrier attached portionsof the envelope, and higher than the bladder neck, tension isnecessarily created in the bladder and envelope Walls. Theseconsiderations must be taken into account in the design of the unit.

Since a unit can be very quickly installed and can be manually tripped,it may be possible in some instances, even after the craft is in serioustrouble, for reserve units to be installed and tripped where, for anyreason, such as lack of foresight, or collision damage to installedunits, reserve units are found to be especially needed.

In accordance with the showing of FIGURE 5, the carrier member of aniniiation unit may 4be clamped by quickly detachable clamping means tothe underside of a seat 98 of an open boat. The unit in such a case maybe like that of FIGURE 1, but relatively small, and the automatic andremote control means may be omitted.

It is advantageous to provide the clamps 100 on the seat 98 fordetachably clamping the carrier 16 of the intiation unit under the seat,so that the unit can be detached and kept under lock and key when theboat is left moored in the water or is left exposed outdoors. The unitcan, of course, be made of a size appropriate to the use for which it isintended.

FIGURE is simply illustrative of the use 0f any suitable clamping means,axed either to any convenient and useful part of the boat, or to thecarrier member of the flotation unit, for quickly and convenientlyattaching the unit to, and removing it from, the boat in any suitablelocation.

I have described what I believe to be the best embodiments of myinvention.

I claim:

1. A otation unit adapted for compact and inconspicuous mounting in acompartment of a boat or other craft which the unit is designed to helpin keeping afloat in an emergency, comprising, in combination,

y(a) a rigid carrying and mounting member,

f b) a metallic tank for containing and making available an iniiatinggas under high pressure,

(c) an inliatable bladder of highly resilient, stretchable material,

(d) connecting means providing a channel of communication between thetank and the interior of the bladder, including a supply valve and apressure regulator, the latter for limiting ination of the bladder tosubstantially a predetermined pressure,

(e) a protective envelope of strong, tough, iieXible, in-

extensible, woven fabric enclosing the bladder for protecting it againstpuncture, and for limiting expansion of it to prevent the occurrence ofbursting strain, and

(f) an easy-tear container surrounding the envelope and normallymaintaining the bladder and the sur rounding envelope in compactlyfolded form, but incapable of resisting inliation of the bladdersubstantially when inflation is initiated,

the envelope and container having portions which are iixedly secured tothe rigid carrying and mounting member, and the construction andarrangement being such that the bladder and envelope, though normallyconfined by the container, are readily freed by it to unfold and expandto the limits prescribed by the envelope in response to inflatingpressure.

2. A flotation unit as set forth in claim 1- in which the bladder is ofrubber, the envelope is of Woven nylon, and the container is of a lesssubstantial material than either of these.

3. A flotation unit as set forth in claim 1 which further includes apressure limiting relief valve in direct communication with the interiorof the bladder.

4. A otation unit as set forth in claim 1 in which the means connectingthe tank with the bladder includes a further channel of communication,in addition to the one containing the supply valve, in which is includeda heat responsive, alternative supply valve for turning on the gassupply automatically in case of tire.

5. A system employing a unit as set forth in claim 1 which furtherincludes means for turning on the supply valve of the unit automaticallyin response to rising water level within the craft.

6. A system employing a plurality of units as set forth in claim 1 whichfurther includes means for individually turning on the supply valves ofthe units by remote manual control from a common control station.

7. A system as set forth in claim 6 which further ncludes means forturning on the supply valves of a plurality of the units simultaneouslyby remote control from the common control station.

8. A flotation unit as set forth in claim 1, in combination lwithquickly detachable, attaching rneans for securing the unit to a selectedportion of the craft.

References Cited UNITED STATES PATENTS TRYGVE M. BLIX, Primary Examiner.

